On 8/27/2012 11:47 AM, Viresh Kumar wrote: > On 27 August 2012 02:11, Hein Tibosch <[email protected] > <mailto:[email protected]>> wrote: > > The dw_dmac driver was earlier adapted to do 64-bit transfers > on the memory side (https://lkml.org/lkml/2012/1/18/52) > This works on ARM platforms but for AVR32 (AP700x) the maximum > allowed transfer size is 32-bits. > This patch allows the arch to set a new slave property > max_mem_width to limit the size. > Allowable values for dw_dma_slave::max_mem_width are: > > 0 : leave it up to dw_dmac (64 bits) > 1 : 16-bits > 2 : 32-bits > > > Either this should be in increasing order or decreasing. That will make it > more sensible, isn't it? > > So it should be: > 0-64bit > 1-32bit > 2-16bit > > Also, i am not sure if we should actually support 16 bit here at all. Maybe > nobody > will have 16 bit requirement. So can remove it for now. If in future it is > required > then can accept that. > Viresh,
If you're OK with the version below, I'll send both dw_dmac patches again as v2 Now cc Vinod Koul and Dan Williams The dw_dmac driver was earlier adapted to do 64-bit transfers on the memory side (https://lkml.org/lkml/2012/1/18/52) This works on ARM platforms but for AVR32 (AP700x) the maximum allowed transfer size is 32-bits. A new 'automatic' config item 'DW_DMAC_MEM_64_BIT' determines if 64-bit memory transfers are allowed. This boolean will be defined on non-AVR32 platforms No arch code will have to be changed to make this patch work. Signed-off-by: Hein Tibosch <[email protected]> --- drivers/dma/Kconfig | 8 ++++++++ drivers/dma/dw_dmac.c | 15 ++++++++++++--- 2 files changed, 20 insertions(+), 3 deletions(-) diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig index 3635daf..82e958f 100644 --- a/drivers/dma/Kconfig +++ b/drivers/dma/Kconfig @@ -97,6 +97,14 @@ config DW_DMAC_BE Say yes if access to the Synopsys DesignWare AHB DMA controller should be big endian, such as for Atmel AT32ap7000 +config DW_DMAC_MEM_64_BIT + bool "Allow Synopsys DesignWare AHB DMA to do 64-bit mem transfers" + default y if !AVR32 + depends on DW_DMAC + help + Say yes if the Synopsys DesignWare AHB DMA controller may do + 64-bit memory transfers + config AT_HDMAC tristate "Atmel AHB DMA support" depends on ARCH_AT91 diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c index 7212961..2be010c 100644 --- a/drivers/dma/dw_dmac.c +++ b/drivers/dma/dw_dmac.c @@ -639,9 +639,12 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, * We can be a lot more clever here, but this should take care * of the most common optimization. */ +#ifdef DW_DMAC_MEM_64_BIT if (!((src | dest | len) & 7)) src_width = dst_width = 3; - else if (!((src | dest | len) & 3)) + else +#endif + if (!((src | dest | len) & 3)) src_width = dst_width = 2; else if (!((src | dest | len) & 1)) src_width = dst_width = 1; @@ -746,9 +749,12 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, mem = sg_dma_address(sg); len = sg_dma_len(sg); +#ifdef DW_DMAC_MEM_64_BIT if (!((mem | len) & 7)) mem_width = 3; - else if (!((mem | len) & 3)) + else +#endif + if (!((mem | len) & 3)) mem_width = 2; else if (!((mem | len) & 1)) mem_width = 1; @@ -813,9 +819,12 @@ slave_sg_todev_fill_desc: mem = sg_dma_address(sg); len = sg_dma_len(sg); +#ifdef DW_DMAC_MEM_64_BIT if (!((mem | len) & 7)) mem_width = 3; - else if (!((mem | len) & 3)) + else +#endif + if (!((mem | len) & 3)) mem_width = 2; else if (!((mem | len) & 1)) mem_width = 1; -- 1.7.8.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
